[ RadSafe ] X-ray Generating Device Compliance

[Neil Walters]

Hi Radsafers!
Question about the radiation emission rates from devices used to scan luggage and packages at airports, govt. buildings, etc...any comments, logic, suggestions, experience or wisdom greatly appreciated.

These devices are manufactured to comply with US FDA emission rate limit defined in 21 CFR 1020.40.(c) "...shall not exceed an exposure of 0.5 milliroentgen in one hour at any point five centimeters outside the external surface".   For the UK and many other European countries that exposure rate limit is 0.1 milliroentgen in one hour at any accessible point.   I have yet to find a list comparing all country regulatory limits for comparison.

However, with so many different regulatory bodies surveying these devices for compliance to their specs and using different survey techniques, different geometry, different survey instruments and different interpretations, etc...I guess I am looking for some common ground here.

I refer to a recent occurrence when a regulatory body (non-US) was surveying a device when a package was entering the tunnel, as it passed through the lead (Pb) curtains, obviously curtains open slightly and they were able to measure greater than 0.1 milliroentgen per hour emission rate in that area for that short time period, thus failing the emission rate limit, but with no regard to cumulative measurements over a 1 hour period.   I guess my question is are there any globally recognized methods, techniques, guidance for regulatory agencies (AND) certification / testing bodies to measure the emission rates of these device and sign off that they are compliant, rather than using an instantaneous rate that is not representative of the true exposure rate during an actual hour?


Thoughts?


Very sincerely,
Neil Walters.